Quorn: A Fungus Among Us

If you shop for meat substitutes, you may have noticed something in the freezer section called Quorn (pronounced “kworn”). It’s the brand name for food products made with mycoprotein, derived from the soil fungus Fusarium venenatum. The fungus is fermented in vats and the resulting paste is mixed with egg whites and flavorings and shaped into various meat-like forms, such as burgers, cutlets, and chicken-like nuggets. Compared to many other meat substitutes, it has a more meaty texture and taste.

Quorn is high in protein and fiber and is a good source of selenium and zinc. Marketers say it helps control cholesterol, blood sugar, and weight. Sounds like a perfect vegetarian option—but it has been the subject of much controversy.

What’s in a name?

Quorn was originally promoted as “mushroom in origin,” which sounds more appealing than calling it a fungus. But mycoprotein is not a mushroom (not all fungi are mushrooms), and the American Mushroom Institute, the Center for Science in the Public Interest (CSPI), and even some other food companies took issue with the labeling. It’s now described as an edible fungus, like mushrooms and truffles—which, as opponents say, is still somewhat deceptive. And it’s hardly all natural, as it’s often touted, since it is highly processed.

A matter of safety

The Food and Drug Administration (FDA) categorizes mycoprotein as GRAS, or generally recognized as safe. However, more than 2,000 adverse reactions have been reported to CSPI, including severe abdominal pain, vomiting, diarrhea, and hives. Several people have suffered breathing difficulties and even anaphylaxis (a life-threatening allergic reaction). At least two deaths have been linked to Quorn, according to CSPI. CSPI has repeatedly urged the FDA to revoke Quorn’s GRAS status, or at least to require warning labels.

Not surprisingly, a mycoprotein website lists a very low estimated risk of adverse reactions and says the "only side effect" that may occur in some people is flatulence, similar to that from other high-firber foods.

What about the health claims?

Several studies, most from the early 1990s, suggest that mycoprotein may have positive effects on cholesterol, blood sugar, and satiety. But they were small, short, and often flawed. Among the more recent studies, a small company-funded one in 2010 suggested a link between mycoprotein and improved cholesterol—but this study had problems, too. Another study, in 2016, reported that mycoprotein (about 5 ounces in a single test meal) decreased calorie intake three hours later, compared to a chicken meal, and also lowered blood insulin levels in a small sample of overweight people, but the long-term effects were not evaluated. The potential health benefits may be due to the specific types of fiber in mycoprotein (beta-glucans and chitin).

Bottom line: There are other meat alternatives, including those made from soy, that don’t carry the risk of serious adverse reactions that have been reported from Quorn, unless, of course, you’re allergic to soy or their other ingredients. Keep in mind that all processed meat substitutes, including Quorn, tend to be high in sodium and sometimes saturated fat from added cheese and other ingredients.